Contact device



Dec. 6, 1949 E. E. A. JOHANSSON CONTACT DEVICE Filed Nov. 50, 1944 INVEXTQR [#1151 E. x gJo/vanss'on ATTORNEYS Patented Dec. 6, 1949 UNITED STATES PATENT OFFICE 2,4.631 I CONTACT DEVICE Ernst Elof Ake Johanmn, Stockholm, Sweden, assignor to Telefonaktiebolaget L M Erlcsson, Stockholm, Sweden, a company of Sweden Application November 30, 1944, Serlal No. 565,948

In Sweden December 10, 1943 side of the rectangular section is perpendicular to the longitudinal direction of the contact strip. The contact surfaces of the second contact strip are generally formed so as to make contact with the sides of the pin that correspond to the long side of the rectangular section. Due to this arrangement it is not necessary to arrange the pins with such a precision in relation to the longitudinal axisof the contact strip as would be necessary if, for instance by means of round contacts, one tried to obtain contact strips that could easily be torn apart or put together. For weak current purposes, for which such contact strips are most often used, it is very important to diminish the dimensions of the device as far as possible, since often a very great number of wires are to be connected in a limited space. It has proved to be diflicult to obtain good metallic contact under all circumstances with the relatively small contact pressures. obtainable in such devices. In many cases this may cause great disturbances. This problem has been treated in many diiferent manners and in such a way that a contact in the one strip that is sliding over a-contact pin when the strips are connected individual contact point, the 'contact possibilities thereby of course being increased. The contact cylinder may also be provided with slits perpendicular to the longitudinal direction in order to increase the number of individual contact points. This contact arrangement is however very bulky, since the contact cylinder necessarily must get rather great dimensions relative the thickness of the flat pin. 4

4 Claims. (CL 173-483) The present invention relates to a contact device of the described type, by which the said disadvantages are eliminated and which may be used inorder to get a great number of contact possibilities in alimited space. The contact device consists of one contact with a number of parts being elastic in a direction perpendicular to the contact surface and a second contact consisting of a contact pin. The contact provided with elastical parts consists of a packet of metal laminas, the plates of which being provided with a slit from one edge of the plate in such a way that there is formed an aperture in the contact perpendicular to the surface of the separate laminas and into which the contact pin may be inserted. The laminas are suitably of an oblong, rectangular form. The slit in the laminas which at the edge of the plate or in the vicinity thereof suitably has a contraction is given such dimensions' that a contact pressure arises when the contact pin is brought into it as the material on each side of the slit is elastic. The contact, in spite of the little thickness of each lamina, has good stability as a number of plates are put together surface to surface and soldered or welded at the non-split parts of the laminas. It is evident' that a very great number of individual contact possibilities are produced by means of this construction. The dimensions of the contact device can be made very small in the longitudinal direction of the complete contact strip,

since not much material on each side of the slit is necessary to obtain a sufllcient contact pressure on the contact surface. Even if very thin laminas are used, which is preferable, a rather great moment of inertia is obtained in the direction in which the laminas are flexible on account of the tight packeting of the laminas. In order to make the device more insensible for external influence the outer laminas in the packet may be made thicker than the inner ones.

The features of the invention will be more fully understood upon consideration of the annexed drawing wherein:

Fig. l is a side elevational view of a flat pin which constitutes one of the contact elements.

Fig. 2 is a similar view taken at right angles 7 to the edge shown in Fig. 1.

3 is a side elevational view of the laminated contact member.

Fig. 4 is a similar view showing the edges of the laminations.

Referring to the drawing there is shown at l a relatively fiat contact pin having a wedge shaped end 8 which forms one of the contact elements. The other contact member includes a plurality of relatively thin metal strips 2 arranged in facial relationship. 3 indicates the slit in the oblong rectangular metal strips 2, into which the contact pin I is to be inserted. i The legs I, obtained in the plate by taking away the material in the slit 3, may suitably be provided with extensions 5 intended to produce small contact surfaces and a comparatively high contact pressure. In this case the slit 3 is of the same width as the pin 1 or somewhat wider and the distance between the extensions 5 on the legs somewhat smaller than the thickness of the pin. The non-split parts of the laminas are wholly or partly soldered or welded together. In this manner a number of contact possibilities corresponding to the number of plates is obtained, each one with a comparatively high contact pressure although the dimensions of the contacts are very small in the longitudinal direction of the final contact strip.

Experiments have proved that perfect contact is immediately obtained with the contact arrangement just described even at a very heavy oxidation of the contact surfaces produced by strong heating. The device has proved to be far superior to'all known constructions with which comparative experiments have been made.

I claim:

1. In a contact device, a stack composed of a pin. ality of relatively thin flat elongated platelike members of flexible material arranged in facially contact relation, means joining said members together at one end to maintain the stack form thereof, said members having registering recesses at the opposite ends forming spaced legs capable of resilient motion in the direction of the plane of the members, said legs having extensions within the recesses presenting at the edges thereof a multiplicity of contact surfaces of small area capable of relative movement incident to the flexing of the legs in conformity with the surface irregularities of a contact member engaged therewith.

spaced legs and a slot therebetween of a greater width than a contact element to be received therein, extensions carried by each of the strips adjacent the free ends of the legs with inner edges of said extensions being spaced from each other a distance less than the width of the contact element to be received therein whereby the edges of the extensions provide a multiplicity of contact surfaces capable of relative movement to conform with surface irregularities of the contact element.

3. In a contact device, a plurality of juxtaposed elongated metal laminations, each of said laminations having a longitudinally arranged slot in an end portion, and means maintaining the metal laminations in said assembled relationship.

4. A contact assembly for a jack switch comprising, a plurality of elongated juxtaposed metal laminations, said laminations having substantially aligned lengthwise slots therethrough so as to be resilient in a. plane of the lamination, and means adjacent unslotted portions of the laminations for maintaining the laminations in said juxtaposed relationship.

ERNST nos AKE JOHANSSON.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITEIJ STATES PATENTS Number Name Date 1,678,508 Hart July 24, 1928 2,029,028 Kneass et al. Jan. 28, 1936 2,205,051 schmitt June 18, 1940 2,292,049 Chirelstein Aug. 4, 1942 

